1. Field of the Invention
The present invention relates to a new primer composition and a method of using the primer composition in the detection of Shigella sonnei. 
2. Description of the Prior Art
Organisms of the genus Shigella cause classic bacillary dysentery that is characterized by severe diarrhea, fever and abdominal pain. Shigella is one of Enterobacteriacea and can be classified into four species: S. dysenteriae, S. flexneri, S. boydii and S. sonnei. Shigella spp. is typically associated with self-limiting infections that are rarely fatal except in children or the elderly. Infection with S. dysenteriae can cause a severe form of the disease with up to 20% of cases proving fatal, such as hemorrhagic colitis and hemolytic uremic syndrome. Although the syndromes caused by the infection with S. flexneri, S. boydii and S. sonnei are not so severe and can be cured by antibiotics, the general use of antibiotics results in the production of strains resistant against antibiotics. Moreover, S. sonnei infection frequently occurs in the industrially developed area. The S. sonnei infection will be popular in the industrial area of a high population density. Normally, the human by intake of 10-100 bacteria cells will be infected (DuPont et al., 1989, J. infect. Dis.).
Morris et al. indicated that the isolation percent of Shigella spp. samples was lower than 25%. That is, more than 75% of samples existing Shigella spp. could not be correctly detected (Morris et al., 1970, Appl. Microbiol.). Polymerase chain reaction (PCR) can be rapid and reliable for detecting bacteria and virus in various samples. It was described in Josephson et al., 1993, App. Environ. Microbiol that the PCR can detect the S. sonnei that cannot be cultivated. However, the method cannot specifically detect the existence of S. sonnei. Accordingly, there is a need to provide a method for a rapid and specific detection of S. sonnie in food and clinical samples.